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                                                       < WHYLLness 004          WHYLLness 006 >

005 Avoid direct exposure to sunlight

The light from the sun contains harmful radiation including ultraviolet rays (UV) (Table 5a). This harmful radiation can damage the skin, cause skin cancer22 and accelerate skin aging.23 Avoiding direct exposure to the sunlight reduces your risk of skin cancer and slows down aging of your skin.



Skin cancer

Sun exposure is a major factor for skin cancer, especially the most deadly type called melanoma. Modern diagnostic methods are available to diagnose skin cancer in addition to standard initial examination using the "ABCDE" technique (Table 5b).



Table 5a. Subtypes of ultraviolet light from the sun.

UV subtypes

Wavelength (nm)

Bad effects



Damage collagen;

Destroy vit. A

Accelerates skin aging



DNA damage, sunburn, skin cancer


Pterygium & pinguecula formation.

Destroy vit A



DNA damage, germicidal



              Some high risk population can be identified using the HARMM criteria (Table 5c) introduced by Goldberg et al.24



Table 5b. "ABCDE" method for identifying suspicious skin lesions to be melanoma.


Asymmetrical skin lesion


Border of the lesion is irregular


Color variation: melanomas usually have multiple colors


Diameter: > 6 mm (though some melanoma are < 6 mm)


Elevation: enlarging or evolving


Vitamin D from sun exposure

              Exposure to the sun stimulates vitamin D production. But you might just need 5-10 minutes exposing your legs and arms to the sun to get enough vitamin D for a day. However because of the harmful effects of the sun, taking food that contains vitamin D is therefore better recommended (see Table 78 in WHYLLness 078])


Table 5c. "HARMM" criteria for high risk population


History of previous melanoma


Age over 50


Regular dermatologist not available


Mole changing


Male gender


When you go out during sunny days, use a visor and an umbrella

              Avoid exposure to sunlight, especially between 10 a.m. and 2 p.m. when the UV intensity is usually high. However if you need to go out in day light, you can protect yourself from the sun's deadly rays. Wearing clothing that covers the whole body or use of an umbrella and a visor that filters UV are best means of protection. Also wear a sunscreen with an SPF of at least 15 [WHYLLness 067].

              People who are taking some types of medication including tetracyclines, doxycyclines and some fertility drugs are more susceptible to the harmful effects of the sun.


Lack of sunlight and depression

              A prolonged lack of sunlight may cloud memory and affect cognitive functions in some people with history of depression.

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